The present invention relates to optical scanning devices and more particularly to a portable scanning device for generating a plurality of different size scan patterns for scanning a coded label.
In present-day merchandising point-of-sale checkout systems, data pertaining to the purchase of a merchandise item is obtained by reading data encoded indicia such as a bar code label printed on or attached to the purchased merchandise item. Reading systems which have been constructed to read this type of bar code include stationary optical scanning systems normally located within the cabinet structure of a checkout counter or hand-held laser scanners which emit a single or multiple line scan pattern which are manually moved past the bar code label that is to be read. In prior scanners, the scan pattern is generated by deflecting a number of scanning light beams off a plurality of pattern mirrors. The number of scanning lines in the scan pattern is determined by the number of scanning beams generated or the number of pattern mirrors utilized. The more lines in the pattern produce a more efficient scanning operation. Depending on the size of the bar code label to be read, prior hand held scanning units have utilized interchangeable scanning heads which produce different scanning patterns which vary in the size and the number of scan lines forming the scan pattern. It would be desirable to have a hand-held scanning unit that would be able to generate a number of different size scanning patterns each of which would scan different size bar code labels with the same efficiency.